In chapter_purist_unit_tests.asciidoc: AssertionError: <MagicMock name='List().owner' id='4522868128'> != <User: User object (a@b.com)>

My code:
```
def new_list(request):
"""
item.objects.create 是创建Item对象的简化方式无需再掉用.save()方法
"""
form = ItemForm(data=request.POST)
if form.is_valid():
list_ = List()
print(request)
list_.owner = request.user
list_.save()
form.save(for_list=list_)
return redirect(list_)
else:
return render(request, 'home.html', {"form": form})
```
```
@patch('lists.models.List')
@patch('lists.forms.ItemForm')
def test_list_owner_is_saved_if_user_is_authenticated(self, mockItemFormClass, mockListClass):
user = User.objects.create(email='a@b.com')
self.client.force_login(user)
#print(settings.AUTHENTICATION_BACKENDS[0])
self.client.post('/lists/new', data={'text': 'new item'})

mock_list = mockListClass.return_value
self.assertEqual(mock_list.owner, user)
```